MetaJobRunnable.java

package de.otto.edison.jobs.domain;

import de.otto.edison.jobs.repository.JobMetaRepository;
import de.otto.edison.jobs.service.JobMetaService;
import de.otto.edison.jobs.service.JobRunnable;

import java.time.Instant;

import static java.time.Instant.ofEpochMilli;

/**
 * Abstract class used to implement stateful jobs.
 * <p>
 *     Provides access to meta information that is persisted between job executions.
 *     Meta data is stored in a {@link JobMetaRepository}.
 * </p>
 */
public abstract class MetaJobRunnable implements JobRunnable {

    private final JobMetaRepository metaRepository;
    private final String jobType;

    protected MetaJobRunnable(final String jobType,
                              final JobMetaRepository metaRepository) {

        this.jobType = jobType;
        this.metaRepository = metaRepository;
    }

    public final String getJobType() {
        return jobType;
    }

    public final void deleteMeta(final String key) {
        checkKey(key);
        metaRepository.setValue(jobType, key, null);
    }

    public final void setMeta(final String key, final String value) {
        checkKey(key);
        metaRepository.setValue(jobType, key, value);
    }

    public final void setMeta(final String key, final int value) {
        checkKey(key);
        metaRepository.setValue(jobType, key, String.valueOf(value));
    }

    public final void setMeta(final String key, final long value) {
        checkKey(key);
        metaRepository.setValue(jobType, key, String.valueOf(value));
    }

    public final void setMeta(final String key, final Instant value) {
        checkKey(key);
        setMeta(key, value.toEpochMilli());
    }

    public final String getMetaAsString(final String key) {
        checkKey(key);
        return getMetaAsString(key, null);
    }

    public final String getMetaAsString(final String key, final String defaultValue) {
        checkKey(key);
        final String value = metaRepository.getValue(jobType, key);
        return value != null ? value : defaultValue;
    }

    public int getMetaAsInt(final String key, final int defaultValue) {
        checkKey(key);
        final String value = getMetaAsString(key);
        return value != null ? Integer.valueOf(value) : defaultValue;
    }

    public final long getMetaAsLong(final String key, final long defaultValue) {
        checkKey(key);
        final String value = getMetaAsString(key);
        return value != null ? Long.valueOf(value) : defaultValue;
    }

    public final Instant getMetaAsInstant(final String key) {
        checkKey(key);
        return getMetaAsInstant(key, null);
    }

    public final Instant getMetaAsInstant(final String key, final Instant defaultValue) {
        checkKey(key);
        final long epochMilli = getMetaAsLong(key, -1);
        if (epochMilli != -1) {
            return ofEpochMilli(epochMilli);
        } else {
            return defaultValue;
        }
    }

    private void checkKey(final String key) {
        if (key == null || key.startsWith("_e_")) {
            throw new IllegalArgumentException("Keys must never be null and must not start with prefix _e_");
        }
    }}